L3-L4 Microkernel FamilyLean, with fast, message-based, synchronous IPC, simply-used external paging mechanisms, security mechanism based on secure domains: tasks, clans, chiefs. Kernels try to implement only a minimal set of abstractions on which OSs can be built flexibly. L3 has system-wide persistence.http://os.inf.tu-dresden.de/L4/

PerseusA secure platform for applications that use digital signatures. Based on L4 and Linux. Research project at Applied Data Security Group, Ruhr-University Bochum., Germany.http://www.perseus-os.org/